The present disclosure relates to an indirect inkjet printing system, and more specifically to an indirect inkjet printing system including a blowing mechanism for preventing condensation on the ink-heads.
There has previously been proposed by the present applicant, for example in WO2013/132418 which is incorporated by reference as if fully set forth herein, a printing system in which, at an image forming station, an aqueous ink is jetted onto an intermediate transfer member (ITM), such as an endless belt or drum. The resulting ink image is transported by the ITM to an impression station and, during its transportation, it is dried to leave behind a tacky ink residue. At the impression station, the ink residue is transferred onto a substrate and the ITM surface then returns to the image forming station to commence a new printing cycle.
Certain problems have been encountered during operation of such a printing system.
First, the ITM is operated at an elevated temperature and the ink droplets start evaporating on impacting the ITM. The released water vapor then condenses on the cooler print heads and forms droplets, which eventually drip onto the ITM and damage the printed image.
Second, when a droplet is jetted by a printing nozzle, it is often followed, a short time after it has separated from the printing nozzle, by a much smaller droplet, referred to as a satellite. Being emitted sequentially while the ITM is in motion, the droplets and their satellites do not fall on the same point on the ITM and therefore result in some image dots on the substrate having a faint shadow caused by their satellites.
There is thus a need in the art for indirect inkjet printing systems which prevent condensation on the print heads and avoid satellite ink drops, so as to prevent distortion of the printed image.
One solution for the problems presented herein are described in WO2017/009722 which is incorporated by reference as if fully set forth herein.